The proposed research is a continuation and logical extension of research initiated under a previous grant. The overarching objective of this program of research is to understand the moderating influences of skill acquisition (e.g., consistency, task structure, learning requirements, amount of practice) as they relate to models developed to describe and predict the influences of aging on performance improvement and learning underlying the acquisition of skill. This program of research has been success in delineating age-related performance improvement and learning underlying acquired skills for several task domains. However, a major gap in the literature concerns long-term retention of acquired knowledge and acquired skills. Indeed, the literature paints a confused picture of age- related retention effects. It is an understanding of this question which will add closure to our investigation of age-related differences in automatic and strategic components of skill acquisition. From a theoretical as well as practical perspective it is critical to have accurate information about how skills and knowledge decay during periods of disuse. The major aims of the current research effort include the following: (l) To develop a general theoretical framework predicting retention of performance as a function of the underlying components of the acquired skill, the length of the retention interval, intervening activities, and age. (2) To understand how the interactions of age, retention interval, and component processes change as the acquired skill increases in complexity. (3) To understand the possible interaction of retention characteristics of strategic and automatic aspects of skill from an age-related perspective. In a related issue, to understand if retention characteristics are domain-specific; that is, dependent on idiosyncratic relations that a person can develop for component processes supporting the skill, or are the characteristics more general as indicated by support of a domain independent model. (4) Develop an understanding of the relationship between age-related characteristics of acquisition and retention of acquired skill. That is, is an age-related model of skill acquisition also capable of predicting retention capability or must acquisition and retention be considered independent factors?